Heating, ventilating, and air conditioning (HVAC) systems have long used sail switches to sense air flow. Sail switches are conventionally mounted inside ductwork which conducts air in HVAC systems. Components of HVAC systems which handle air may not be enclosed in ductwork, housings, and the like, may require monitoring of air flow therethrough to maintain efficient operation and avoid catastrophic component failure. An example is a condenser of an air conditioning system. Condensers are usually located outdoors, where they are susceptible to full or partial clogging by leaves, trash, and other contaminants. Significant obstruction of air flow by contaminants leads to inadequate cooling of refrigerant within the condenser.
Air flow through condensers has been monitored inferentially. That is, typically, a sensor such as a temperature sensor is located at a selected point along a conduit conducting refrigerant which has been cooled in the condenser. If the refrigerant has not been sufficiently cooled, lack of sufficient air flow, a frequent cause of inadequate cooling of refrigerant, may reasonably be suspected.
Inferential sensing of condenser obstruction is not unreasonable. However, other causes of inadequate cooling of refrigerant may be present, thereby causing inferred failure of air flow to be spuriously reported. Also, sensors placed in a refrigerant line are subject to inaccuracy and leaks.
Sail switches used in other applications are subject to being ineffectively located within an air stream. This may be, for example, because a suitable mounting location for a sail switch may not be in accord with the best placement of the sail switch.
A need remains for improving effectiveness and versatility of sail switches.